Rivermatics

USGS Streamgage 11289651

Combined Flow Tuolumne River + Modesto Cn + Turlock Cn

Combined Flow Tuolumne River + Modesto Cn + Turlock Cn is USGS streamgage 11289651 in California, monitoring river discharge in hydrologic subbasin 18040009. It drains a watershed of about 1,538 square miles. Discharge records at this site go back to 2025. Typical flow runs near 2,877.1 cfs in July and 2,480 cfs in April, with the higher of the two arriving in July.

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Gauge details

State
California
Drainage area
1,538 sq mi
Subbasin (HUC-8)
18040009
Coordinates
37.66632, -120.44214
USGS site number
11289651
Records begin
2025-11-25 (1 years)

Typical flow by month

Long-term daily discharge percentiles from the USGS record (up to 55 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.

Historical monthly discharge percentiles in cubic feet per second
Month Low p10 Typical p50 High p90 Range
January 162.7 487.3 4,382.9
February 161.9 739.6 5,417.2
March 318.1 1,794.5 6,838.4
April 940.3 2,480 8,637.7
May 1,112.2 2,573.9 8,687.1
June 1,442.6 2,551.3 6,760
July 1,787 2,877.1 4,488.7
August 1,443.5 2,500.6 3,768.7
September 551.4 1,553.7 3,025.7
October 238.2 1,092.1 2,486.1
November 166.9 415.7 1,668.4
December 165.5 373.7 2,792.9

All values in cubic feet per second (cfs).

Common questions

When does Combined Flow Tuolumne River + Modesto Cn + Turlock Cn normally run highest?
July, on the long-term record. The median daily flow that month is about 2,877.1 cfs, against 373.7 cfs in December, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
What is a normal flow for Combined Flow Tuolumne River + Modesto Cn + Turlock Cn?
It depends on the month. In January, half of days historically fall near 487.3 cfs, with the middle 80% of days between 162.7 and 4,382.9 cfs. The month-by-month table on this page gives the full range.
How long has Combined Flow Tuolumne River + Modesto Cn + Turlock Cn been measured?
Discharge records at USGS site 11289651 begin in 2025, about 1 years, covering roughly 9,125 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
Where is Combined Flow Tuolumne River + Modesto Cn + Turlock Cn?
The gauge sits at 37.66632, -120.44214, in California, in hydrologic subbasin 18040009, draining roughly 1,538 square miles.
Can I use Combined Flow Tuolumne River + Modesto Cn + Turlock Cn data for flood or safety decisions?
No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.

Other gauges in this subbasin